The present invention relates to a coring reamer. More particularly, it refers to an improved guide bushing for a coring reamer, a storage package for a coring reamer assembly, and a method of using the coring reamer.
In the prior art, it is well known to use a coring reamer to cut a cylindrical bone tunnel at a surgical site. The reamer is coupled to a handpiece that rotates the reamer to facilitate cutting a bone tunnel. For this purpose, the reamer has a cylindrical distal end with sharp teeth formed thereon.
It is also well known to guide such a reamer by employing a guide pin separately and previously driven into or through the bone at the surgical site. As the reamer cuts the bone tunnel, the reamer slides over the guide pin to guide its motion. While the prior art contemplates an interface between the guide pin and the reamer, one aspect of the present invention proposes an improvement thereover.
In U.S. Pat. No. 5,423,823 to Schmieding, the guide pin has an enlarged collar that guides the reamer over its peripheral edges. This collar is fixedly mounted on the guide pin or integrally formed therewith and facilitates removing the core from the coring reamer. A prior U.S. Pat. No. 4,696,308 to Meller et al. shows a guide pin with a cylindrical bushing having a cylindrical exterior and a passage therethrough allowing it to be freely slidably mounted over a guide pin. U.S. Pat. No. 5,197,967 to Wilson teaches a trephine instrument including a reamer with a blind passageway therethrough in which is freely slidably mounted a piston having enlarged distal and proximal flanges with the piston being spring biased into the distal direction. The piston is not easily removable from the trephine and the instrument is so designed that any bone core formed by the trephine can be removed by leaving the core attached at one end and pulling the instrument away so the core can be broken off at its distal end. None of this prior art has the advantages of the subject invention.
Applicants are aware of no known prior art relating to handling a reamed bone core other than simply pushing/pulling it out of a reamer onto a surface. Also applicants are not aware of any prior related to packaging suitable for storing coring reamers and usable thereafter to facilitate removal of a bone core from the reamer.
The present invention relates to an improved guide bushing for a coring reamer, a storage package for the reamer assembly, and a method of using the coring reamer. The present invention includes the following interrelated objects, aspects and features:
(1) In a first aspect, the present invention contemplates employing a coring reamer having a cylindrical passageway extending completely therethrough. The coring reamer has a proximal coupling enabling it to be coupled to an adapter which is coupled to a handpiece such as a drill or other instrument designed to impart rotary motion to the reamer. The distal end of the reamer includes a set of teeth surrounding the opening extending therethrough.
(2) The present invention further contemplates a guide bushing consisting of a tapered member having its largest diameter at its proximal end with respect to the reamer and wherein the guide bushing engages an internal cylindrical surface of the reamer with a line contact at its distal end. The guide bushing has a passage extending therethrough sized to slidably receive a guide pin. In a preferred embodiment, the guide bushing is pre-assembled with the coring reamer.
(3) Prior to the reamer being employed, a guide pin is driven into a bone at the surgical site. The reamer/bushing assembly is slid over the guide pin into contact with the bone. Alternatively, if the bushing and reamer are not pre-assembled, the bushing is slid over the guide pin into contact with the bone and the reamer is advanced over the guide pin until the bushing has entered the distal end of the passageway through the reamer.
(4) The handpiece is activated, causing the reamer to rotate, and the surgeon applies a forward pushing force in the distal direction, thereby causing the reamer to excavate a tunnel in the bone. As this excavation takes place, the bushing advances proximally within the reamer while the excavated bone enters the passageway through the reamer with the bone material engaging the distal surface of the bushing throughout the procedure.
(5) Once the tunnel has been formed through the bone, the guide pin, with the reamer attached and with the excavated bone material within the reamer, is removed from the surgical site. A storage package specifically designed for the storing and shipping of the reamer/bushing assembly and, in the preferred embodiment, attaching it to a handpiece is employed to remove the excavated bone core from within the reamer.
(6) The package includes a transparent tube having a closed distal end and an open proximal end, with the open proximal end being closable with a special cap having a central opening therethrough sized to receive, in coupling relation, the proximal coupling of the coring reamer. The proximal coupling of the coring reamer has a polygonal or other non-circular surface at one portion thereof that mimics a corresponding polygonal or other non-circular surface within the opening formed within the cap. The cap has an enlarged periphery allowing it to be gripped by the fingers of the surgeon or other person.
(7) After the tunnel has been formed, the coring reamer is placed through the cap of the tube, with the adapter that coupled the coring reamer to the handpiece installed on the reamer and extending outside the package tube. A wrench is placed over the adapter and is turned while the user grips the peripheral surfaces of the cap to prevent rotation of the coring reamer, thereby allowing the adapter to be removed from the coring reamer. Thereafter, a plunger is inserted through the opening through the coring reamer from the proximal end thereof and is pushed therethrough until the bone core and bushing fall out of the distal end of the coring reamer and into the tube. Thereafter, the bone core may be removed and the coring reamer, bushing, tube and cap disposed of properly. It should be noted that the storage package can be used to initially couple the coring reamer/bushing assembly to the coupling adapter for assembly on to the handpiece.
As such, it is a first object of the present invention to provide an improved guide bushing for a coring reamer, a storage package for the reamer assembly, and method of using these elements in performing surgery.
It is a further object of the present invention to provide such a device in which the guide bushing engages an inner cylindrical passageway through the coring reamer with a line contact to reduce frictional interaction therebetween.
It is a further object of the present invention to provide such a device wherein the guide bushing includes an internal passageway sized to slidably mount the guide bushing over a guide pin.
It is a still further object of the present invention to provide such a device wherein a package is provided to ship the reamer and bushing assembly to the user. Such package also is used to facilitate removal of a bone core therefrom after the reamer assembly has been used.
It is a still further object of the present invention to provide such a device wherein the package includes a cap having an enlarged periphery allowing the cap to be non-rotatably gripped by a surgeon to allow attachment and removal of a proximal adapter from the reamer.
It is a still further object of the present invention to provide such a device including a plunger sized and configured to slide though the opening through the reamer to allow removal of a bone core and the guide bushing after the reamer has been used.
These and other objects, aspects and features of the present invention will be better understood from the following detailed description of the preferred embodiments when read in conjunction with the appended drawing figures.